The present invention relates to an organic EL display apparatus, and more particularly, to a see-through display apparatus which permits light to pass through an image display area of the display apparatus.
Organic electro-luminescence (hereinafter called “organic EL”) displays which make use of a light emitting phenomenon of organic substance have been progressively developed in recent years as candidates for the next generation by virtue of their advantageous features over liquid crystal displays and plasma displays, including a higher image quality, increasingly more potential reduction in thickness, higher luminance, higher definition, lower power consumption, and the like. Organic EL displays have been commercially available for displays intended for use in a variety of electronic devices, for example, a television set, a car navigation system, a portable terminal, and the like.
Such an organic EL display comprises a display screen which is constructed by forming a light emitting element (organic EL element) so as to sandwich an organic substance, which serves as a light emitter, between both negative and positive electrodes, and arranging a large number of light emitting elements over a two-dimensional plane as pixels.
Also, a transmission-type display (see-through display) can also be implemented if organic EL elements are used. For example, the transmission-type display allows a user to observe an image produced on a back side of a screen from a front side of the screen, or a see-through display may be overlaid on a variety of indicators such as an instrument panel (car equipped meters) of an automobile, such that the user is allowed to switch a front-side image provided by the see-through display to the indicators behind the display, and vice versa for viewing a desired one (see, for example, Patent Document 4 listed below). In this way, the organic EL see-through displays are expected to provide a variety of use forms different from conventional displays which can simply irradiate light from a screen to display an image, and have the capabilities to expand functions and designing potential provided by the displays.
Such organic EL displays have been disclosed by the following Patent Documents, and Patent Documents 4-8 in particular are directed to see-through displays.
Patent Document 1: JP-A-9-148074 (Japanese Patent No. 2770013);
Patent Document 2: JP-A-8-185984 (Japanese Patent No. 3560375);
Patent Document 3: JP-A-10-294182;
Patent Document 4: JP-A-2001-148292;
Patent Document 5: JP-A-2002-289362;
Patent Document 6: JP-A-2002-334792;
Patent Document 7: JP-A-2005-108672;
Patent Document 8: JP-A-2006-234963.